Codechange: Use reusable temporary buffer in Win32FontCache. (#12666)

This avoids allocating and deleting a temporary buffer for every glyph that is rendered into a sprite.

src/os/windows/font_win32.cpp

@@ -10,7 +10,6 @@
 #include "../../stdafx.h"
 #include "../../debug.h"
 #include "../../blitter/factory.hpp"
-#include "../../core/alloc_func.hpp"
 #include "../../core/math_func.hpp"
 #include "../../core/mem_func.hpp"
 #include "../../error_func.h"
@@ -209,7 +208,7 @@ void Win32FontCache::ClearFontCache()
 	if (width > MAX_GLYPH_DIM || height > MAX_GLYPH_DIM) UserError("Font glyph is too large");
 
 	/* Call GetGlyphOutline again with size to actually render the glyph. */
-	uint8_t *bmp = new uint8_t[size];
+	uint8_t *bmp = this->render_buffer.Allocate(size);
 	GetGlyphOutline(this->dc, key, GGO_GLYPH_INDEX | (aa ? GGO_GRAY8_BITMAP : GGO_BITMAP), &gm, size, bmp, &mat);
 
 	/* GDI has rendered the glyph, now we allocate a sprite and copy the image into it. */
@@ -259,8 +258,6 @@ void Win32FontCache::ClearFontCache()
 
 	this->SetGlyphPtr(key, &new_glyph);
 
-	delete[] bmp;
-
 	return new_glyph.sprite;
 }
 

src/os/windows/font_win32.h

@@ -10,6 +10,7 @@
 #ifndef FONT_WIN32_H
 #define FONT_WIN32_H
 
+#include "../../core/alloc_type.hpp"
 #include "../../fontcache/truetypefontcache.h"
 #include "win32.h"
 
@@ -25,6 +26,8 @@ class Win32FontCache : public TrueTypeFontCache {
 	SIZE glyph_size;      ///< Maximum size of regular glyphs.
 	std::string fontname; ///< Cached copy of loaded font facename
 
+	ReusableBuffer<uint8_t> render_buffer; ///< Temporary buffer for rendering glyphs.
+
 	void SetFontSize(int pixels);
 
 protected: